Railway-traffic-controlling apparatus



March 11,, 1930. H. A. THOMPSON 1,750,441

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 22, 1926 2 Sheets-Sheetl INVENTOP I w. QDTLM March 11, 1930.

H. A. THOMPSON RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May '22, 19262 Sheets-Sheet 2 Patented Mar. 11, 1930 UNITED STATES PATENT OFFICEHOWARD A. THOMPSON, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THEUNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA-TION OF PENNSYLVANIA RAILWAY-TRAFFIC-CONTROLLING APPARATUS Applicationfiled May 22, 1926. Serial No. 110,922.

My invention relates to railway traflic controlling apparatus, andparticularly to the trackway portion of an automatic train controlsystem.

More particularly my invention comprises means for transmitting traincontrol energy and for operating the signals in a three block indicatingsystem without the use of line wires between the signal locations.

I will describe two forms of apparatus embodying my invention, and willthen point out the novel features of my invention in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing oneform of trackway apparatus embodying my invention. Fig. 2 is a view of amodification also embodying my invention.

Similar reference characters refer to similar parts in both views.

In Fig. 1, reference characters 1 and 1 designate the track rails of arailroad over which traflic normally moves in the direction indicated bythe arrow. These track rails are divided,.by means of insulated joints2, into a pluralit of successive track sections A-B, B-O, D, etc.

Each track section is provided with a polarized track relay designatedby the reference character R with an exponent corresponding to thelocation and connected across the rails near the entrance end of thesection. Current is supplied to the track rails from a suitable sourceof direct current, such as a battery 4 connected across the track railsnear the exit end of the section. A resistor 5 is connected between eachbattery 4 and one rail of the corresponding track section in the usualmanner, and a pole changer 21 and relay contact 29 are included in eachtrack circuit for reasons which will appear hereinafter.

Each section is also provided with a trackway signal designated by thereference character S with an exponent corresponding to the location.These signals may be of any suitable form and are shown as semaphoresignals comprising an upper arm 39 capable of indicating stop, cautionor proceed, and a lower arm 40 capable of indicating stop or proceed.\Vhen upper arm 39 is in the 45 or caution position and lower arm 40 isin the zero or stop position the signal S indicates proceed, prepared tostop at the next signal which I shall designate an alert indication.When arm 39 is in the 45 position and arm 40 is in the 90 position thesignal S indicates proceed, prepared to pass next signal at medium speedwhich I shall designate a caution indication. Since the position of arm40 is changed from the zero position only when giving the cautionindication, the proceed and stop indications correspond to those usedfor ordinary single-arm threeposition signals.

The upper arm 39 of each of the trackway signals is controlled throughthe contacts of two slow-acting relays designated by referencecharacters K and L with an exponent corresponding to the location, theserelays being, in turn, controlled by the neutral contacts of thepolarized track relay of the corresponding track section. When, forexample, relay B is energized, relay L will also be energized over acircuit from battery G through wire 6, front contact 715 of relay R wire8, relay L and wire 9 to battery. Energization of relay L closes itsfront contacts 10 and 11 to complete a caution indication circuit forarm 39 of signal S from battery G through wire 12, front contact 10-10of relay L wires 20 and 13 operating mechanism for arm 39, wire 14,front contact 11 of relay L and wire 9 to battery.

The lower arm 40 of each signal is controlled through a back contact4142 of the associated relay K and a polar contact 28 of the associatedrelay R. The arm 40 can assume the 90 degree position only when both ofthese contacts are closed. The circuit for the arm 40 is from battery Gthrough wire 12, contact 10-10 of relay L wire 20, polar contact 28 ofrelay R wire 32, contact 4142 of relay K wire 43, operating mechanismfor arm 40 of signal S wire 14, contact 11 of relay L and wire 9 back tobattery. It will thus be seen that with relays R and L energized arm 39of signal S will be in the 45 position and the circuit for relay K willbe open at the back contact 7-16 of relay R Contact 4142 of relay Kbeing open, arm 40 will be in the zero or stop position.

The circuit for relay K is from battery G wire 6 back contact 716 ofrelay R wire 33, relay K and wire 9 back to battery G. If the frontcontacts of relays K and L are closed simultaneously, current will flowfrom battery G through wire 12 front contact 1010 of relay L contact 17of relay K wire 18, operating mechanism of arm 39 of signal S wire 14,front contact 11 of relay L and wire 9 to battery G When this circuit isclosed arm 39 is in the 90 or proceed position. WVhen relay L isdeenergized the operating circuits for both arms 39 and 40 of signal Sare opened and the signal then displays a stop indication.

Each section is provided with means for supplying alternating traincontrolling current to the track rails. For this purpose I provide atrack transformer designated by reference character T with anappropriate exponent having its secondary winding 22 connected in serieswith the corresponding track battery 4, resistor 5 and pole changer 21.An impedance 23 is connected in circuit between the secondary 22 of eachtrack transformer T and the associated pole changer 21 in the usualmanner. Each transformer T is at times supplied with alternating currentfrom an associated line transformer designated by the referencecharacter H with an exponent corresponding to the location. The primary26 of each line transformer H is constantly supplied with alternatingcurrent from a source, such as an alternator X, over line wires 3 and 3.

The primary 24 of each track transformer T is controlled by a polarcontact 27 of the adj acent track relay R and also by a front contact 31of the adjacent relay L. It will thus be seen that de-energization of aslow acting relay such as L will open contact 31 and interrupt the flowof current in primary 24 of the adjacent track transformer T, and hencethat train controlling current can never be supplied to the track railsof a sect-ion when polar contact 27 of the track relay R or frontcontact 31 of the relay L for the section next in advance is opened.

In circuit with polar contact 28 of each track relay R is a codingdevice which as here shown is a flasher relay designated by thereference character F with an appropriate exponent. The circuit for thisrelay includes its own front contact 30 so that when energized byclosing of polar contact 28 it will pe-' relay F will open contacts 29and 30 thus deenergizing the relay and opening the circuit of thesecondary of track transformer T and track battery 4 until contact 30falls by gravity to again energize the relay. Alternate opening andclosing of contacts 29 and 30 will take place as long as contacts 1010and 28 remain closed. Assuming the primary 24 of track transformer T Cto be closed at contacts 27 and 31, operation of relay F C will causeintermittent alternating train control current and pulsating directcurrent to be supplied to track section B-O.

Upper arm 39 of each trackway signal controls a pole changer 21 which isin circuit with track battery 4 of the section in rear of the signal.Each pole changer 21 occupies one position when the arm 39 of theassociated signal is in the 45 or 90 position and the other positionwhen the arm is in the zero position. When a signal such as S indicatesproceed, caution or alert section BC is supplied with track circuitcurrent of one polarity which I shall term normal polarity, and relay Bis energized in the normal direction, thus closing polar contacts 27 and28. When signal S indicates stop, section 13-0 is supplied with trackcircuit current of the opposite polarity, which I shall term reversepolarity, and relay R is energized in the reverse direction to opencontacts 27 and 28 by swinging them to the right. Track circuit currentis supplied constantly when contact 29 remains closed due tode-energization of the associated flasher relay F, but when a flasherrelay such as F is energized the supply of track circuit current isintermittent and this relay is so timed that relay R will operate itsneutral contacts 15 and 16 at such rate that the front contactscontrolled by slow acting relays K and L remain closed.

It will now be clear that when a track section such as C-D is suppliedwith current of reverse polarity the polar contact 28 of the track relayR will be open and the o crating mechanism for arm 40 can never eenergized to allow the signal S to indicate caution under theseconditions. If the section CD is supplied with current of normalpolarity the polar contact 28 remains closed and arm 40 assumes the 90position when relay K is tie-energized so that its back contact 41-42closes.

The trackway apparatus herein shown and described may be used with traincarried governing means which will give a less restrictive indication,as a proceed indication, when a train occupies a track section which isintermittently supplied with alternating train controlling current, butwill give a more restrictive indication, such as a stop indication, whenthe supplyof train controlling current is suspended.

As shown in the drawing the section at the right of point D is occupiedby a train V. Relay R is de-energized and its back neutral contact 716is therefore closed to complete a circuit for slow acting relay K frombattery G through contact 716, wire 33, relay K and wire 9 back tobattery. Contact 715 of relay R being open, relay L is de-energized andits front contacts 1010 11 and 31 are opened. Under this condition thesignal S indicates stop because the circuits for the operating mechanismare opened at front contacts l()10 and 11 of relay L and back contact41-42 of relay K Opening of contact 10l0 also cuts off the supply ofcurrent to flasher relay F D by breaking the circuit which may be tracedfrom battery G through wire 12, contact 101O of relay L wire 20, contact28, wire 32, contact 30, relay F and Wire 9 to battery. De-energizationof relay F leaves contact 29 closed so that track circuit current ofreverse polarity is constantl supplied to track section CD by trackbattery 4, the pole changer 21 having been placed in reverse position bythe signal S going to the stop position. N 0 train controlling currentis supplied to section CD because the primary of track trans former T isopen at contact 31.

Relay R is energized thus closing neutral contact 15 and energizingrelay L so that signal S gives an alert indication. Polar contacts 27and 28 of relay R are open because section CD is supplied with trackcircuit current of reverse polarity, hence, the operating circuit forarm 40 is open at 28 and this arm remains in the zero position. No traincontrolling current is supplied to section BC because polar contact 27is open.

Flasher relay F is de-energized due to opening of polar contact 28, andhence contact 29 is closed and track circuit current of normal polarityis supplied to section B-C by battery 4.

Relay R is energized to close contact 7-15, and since section BC issupplied with track circuit current of normal polarity contacts 27 and28 are closed. Relay L is energized and closes the circuit for flasherrelay F B which operates to periodically open and close contacts 30 and29. WVhile flasher relay F is in operation, current is intermittentlysupplied to track relay R so that this relay is alternately energizedand de-energized, with the result that relays L and K are alternatelyenergized. The characteristics of relays L and K are such that the frontcontacts of each of these relays remain closed during the intervals inwhich the flasher relay is de-energized while it is in operation. Theopening and closing of contact 29 supplies intermittent alternating tramcontrol current to section AB from track transformer T the primary ofwhich remains closed at contacts 27 and 31. Opening and closing ofcontact 29 also supplies pulsating U1 UILOIHU.

direct current to the section A-B from track battery 4. Contact 10l0 ofrelay L is closed, but contacts 17 and 41-42 of relay K are open, hencethe signal S indicates caution. It is clear, therefore, that this systeminherently distinguishes the indications of the two signals in rear ofan occupied block, because one of the associated sections is suppliedwith track circuit current of reverse polarity to open polar contact 28and thus open the operating circuit for arm 40 of the signal S, whilecurrent of normal polarity is supplied to the adjacent section in therear and since polar contact 28 is therefore closed, the arm 40 will bemoved to the position. The flasher relay F is so timed that the frontcontacts of slow acting relays- K and L remain continuously closed. Thesignal S indicates proceed so long as relay K holds its contact 17closed and contact 41-42 open and relay L holds its contact 10l0 closedand cannot so indicate unless this is true. Hence a failure of flasherrelay F or a failure of track relay R to keep in step with the periodiccurrents supplied to it will always cause a more restrictive signalindication. Either condition mentioned will cause either contact 15 or16 of track relay R to remain closed to de-energize either relay L or K.If relay K is de-energized the signal S will indicate caution or alertdepending upon the polarity of the track circuit current supplied to thesection and if L is de-energized it will indicate stop.

The signals are controlled in accordance with what is known as threeblock indication, that is, the two signals next in the rear of a stopsignal give a more restrictive indication and the third signal in therear of a stop signal indicates proceed. For purposes of thisapplication the indications will be designated stop, alert, caution andproceed, respectively.

If, under the conditions shown in Fig. l a second train proceeds throughthe stretch of track it will receive intermittent train controllingenergy as far as point B where the supply will be cut off and no traincontrolling energy will be received between points B and D.

The apparatus shown in Fig. 1 is designed for use with a train controlsystem in which the locomotive equipment responds to intermittentalternating train control current. The'operation of the flasher relayssupplies the track sections simultaneously with pulsating direct trackcircuit current and intermittent alternating current whenever twosections in advance are unoccupied. If it is desired to use this systemin connection with locomotive equipment which is not designed to operateon intermittent alternating train control current, the trackwayapparatus may be modified as shown in Fig. 2.

Referring now to Fig. 2 the parts with the exception of the circuits forthe track circuit and train control currents are arranged exactly as inFig. l. The secondary 22 of track transformer T and track battery 4 arehere connected in parallel, and only the branch including track batteryl is interrupted by flasher relay contact 29. lVhen the section ahead ofpoint A. is supplied with pulsating track circuit current of normalpolarity, track relay R alternately closes contacts 7l5 and 7-l6 to holdthe contacts of relay L closed; contact 17 of relay K closed and 4l-12open, hence signal S indicates proceed. Relay L holds its front contact31 closed, and since track circuit current of normal polarity, is beingsupplied to relay R polar contact 27 is closed to complete the primarycircuit of transformer T This circuit is from secondary 25 oftransformer H through wire 36, front contact 31 of relay L wire 37,polar contact 27 of relay R wire 38, primary 24 of track transformer Tand back to secondary 25. lVith this circuit closed alternating traincontrol current is continuously supplied to the track section throughwires 34 and 35.

Polar contact 28 of relay R being closed simultaneously with polarcontact 27, flasher relay F will be operated by current supplied frombattery G through wire 12, front contact 10 10 of relay L, polar contact28, wire 32, contact 30 of relay F rela'y F and wire 9. Operation ofrelay F A will alternately open and close contact 29 so that surges ofdirect current from battery 4 are superimposed upon the train controlcurrent supplied to the track section through Wires 34 and 35.

Although I have shown and described only two forms of railway trailiccontrolling apparatus embodying my invention, it is understood thatvarious changes and modifications may be made therein within the scopeof the appended claims without departing from the spirit and scope of myinvention.

Having thus described my invention what I claim is:

1. In combination, a plurality of successive sections of railway track,a polarized track relay connected across each section, a plurality ofslow release relays associated with each section and controlled by thetrack relay of the corresponding section, a coding device controlledjointly by one slow release relay and a polar contact of the track relayat each section, and means controlled jointly by said slow release andcoding devices and a polar contact of a track relay for supplying traincontrolling current to the track sections.

2. In combination, a plurality of sections of railway track, a trackrelay connected with each section and having neutral and polar contacts,and two slow-acting relays and a coding device associated with eachtrack section, the slow-acting relays being controlled by the neutralcontacts of the track relay and the coding device being controlledthrough a polar contact of said track relay.

3. In combination, a forward, a middle, and a rear section of railwaytrack, a track relay connected across each section, a source of trackcircuit current for each section, a plurality of slow-acting relays anda coding device controlled by each track relay, and means controlled bythe slow-acting relays and coding devices for supplying traincontrolling current to said rear section of track only when said forwardand middle sections are unoccupied.

4. In combination, a plurality of successive sections of railway track,a source of track circuit current for supplying current of normal orreverse polarity depending upon traffic conditions in advance, apolarized track relay for each section, a coding device for each sectionand means controlled by the associated track relay for operating saidcoding device, a source of train control current, and means controlledby the coding device for supplying intermittent train control current toone track section when one of the two sections next in advance issupplied with track circuit current of normal polarity and the othersection is supplied with track circuit current of reverse polarity.

5. In combination, a plurality of successive sections of railway track,a source of track circuit current for supplying current of normal orreverse polarity depending upon traffic conditions in advance, apolarized track relay for each section, a coding device for each sectionand means controlled by the associated track relay for operating saidcoding device, a source of train control current, and means controlledby said coding devices for simultaneously supplying intermittent'traincontrol current and pulsating track circuit current to one track sectionwhen one of two sections next in advance is supplied with track circuitcurrent of normal polarity and the other section is supplied with trackcircuit current of reverse polarity.

6. In combination, a plurality of successive sections of railway track,a track relay for each section. a plurality of slow release relayscontrolled by each track relay, a coding device for each section jointlycontrolled by the track relay and a slow release relay of each section,a source of track circuit current, a source of train control current;and v rality of slow release relays for each section and controlled bythe neutral contacts of the associated track relay, a. coding device foreach section controlled jointly by one of said 5 slow release relays anda polar contact of the track relay of the corresponding section, andmeans controlled by a coding device for simultaneously supplyingintermittent train control current and pulsating track circuit currentto each section when the next two sections in advance are unoccupied.

8. In an automatic train control system, a plurality of successivesections of railway track, a track relay connected to each section,

a plurality of slow release relays for each section controlled by thetrack relay of the corresponding section, a coding device for eachsection controlled by a slow release relay of the corresponding section,a source of track circuit current and a source of train control currentfor each section, and means controlled by the coding device of onesection for normally and simultaneously supplying the preceding sectionwith train control current and track circuit current.

9. In combination, a railway track divided into sections, a source oftrack circuit current for each section, a track relay for each sectionresponsive to reversals of the polarity of the track circuit currentsupplied to the section, two slow acting relays for each section onecontrolled by a front contact of the associated track relay and theother controlled by a back contact of the associated 5 track relay, asignal for each section controlled by the slow acting relays for thesection and arranged to indicate caution or alert when the first relayis energized and proceed when both said relays are energized, a pole- 40changer associated with each signal for causing the track circuitcurrent for the section in the rear to be of normal polarity when thesignal indicates proceed, caution or alert and of reverse polarity whenthe signal indicates stop, and means operating when and only when thetrack relay for a given section is energized in normal direction toperiodically interrupt the supply of track circuit current to thesection next in the rear.

10. In combination, a railway track divided into sections, a source oftrack circuit'current for each section, a polarized track relay for eachsection, two slow-acting relays for each section, one controlled by afront contact of 5 the associated track relay, and the other by a backcontact of the associated track relay, a signal for each sectioncontrolled by the slow-acting relays for the section and arranged toindicate caution or alert when the a first relay is energized andproceed when both of said relays are energized, a polechanger associatedwith each signal for causing the track circuit current for the sectionin the rear to be of normal polarity when 5 the signal indicatesproceed, caution or alert,

and of reverse polarity when the signal indicates stop, a tracktransformer for each section for supplying train controlling current tothe sections, the primary of each transformer being controlled by apolar contact of the track relay of the section next in advance, and acoding device operating when and only when the track relay for a givensection is energized in normal direction to periodically interrupt thesupply of track circuit and train controlling current to the sectionnext in the rear.

11. In combination, a railway track divided into sections, a source oftrack circuit current for each section, a polarized track relay for eachsection, two slow-acting relays for each section one controlled by afront contact of the associated track relay and the other controlled bya back contact of the as sociated track relay, a signal for each sectioncontrolled by the slow-acting relays for the section and arranged toindicate caution or alert when the first relay is energized and proceedwhen both of said relays are energized, a pole-changer associated witheach signal for causing the track circuit current for the section in therear to be of normal polarity when the signal indicates proceed, cautionor alert, and of reverse polarity when the signal indicates stop, acoding relay having a winding and a back contact in series, said codingrelay being controlled by a polar contact of the track relay of a givensection, the polar contact being closed only when the section issupplied with track circuit current of normal polarity, and a secondback contact on said coding relay for controlling the supply of trackcircuit current to the track section in the rear of said section.

In testimony whereof I aflix my signature.

HOWARD A. THOMPSON.

